Was going to pull the C6 out of the motorhome and rebuild it, noticed yesterday that not only do I have no forward gears, I also have a 6" crack in the top of the bellhousing. Crack is between top bolt and the bolt below it on the right side, strange. I'm not out with it yet so I don't know what happened inside of the bellhousing.

Looking for a core, some have ribs and some don't. Being they used these trans for about 30 years, if I'm looking for a core which would be the best one to look for. Year and model?? F350 maybe.